Pneumatic door-check



(No Model.)

S. PORTER.

PNBUMATIO DOOR CHECK.

Patented Oct. 7,1884.

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STEPHEN PORTER, OE BOSTON, MASSACHUSETTS.

PNEUMATiC DOORMCHECK.

SPECIFICATION' forming part of Letters Patent No. 306,351, dated October7, 1884.

Application filed December 17, 1883.

To all whom may concern:

Be it known that I, STEPHEN PORTER, of Boston, in the county of Suffolkand State of Massachusetts, a citizen of the United States, haveinvented certain new and useful Improvements in Door-Ohecks, of whichthe following is a specication.

My invention relates to that class of contrivances known asdoor-checks,77 in which the resistance ot' a body of compressed air isopposed to the closing movement of a door, so that its slamming or noisyclosing is prevented, and it has for its object to provide means wherebya noiseless closure of the door will be automatically effected.

My invention inthe best form now known to me is illustrated in theaccompanying drawings, in which Figure l shows aside view, and Fig. 2 asectional view, looking from the top of a door-check andspring embodyingmy invention as applied ready for use.

My improved door-check contains the fea tures of an air-compressionchamber; also, a spring for closing the door against the resistance of abody oi compressed air, means for regulating the tension of the saidspring, and suitable `ineans for applying the device as a whole inproper position with regard to the door upon which it is to operate.

My present invention consists in improvementsin the means of compressingthe air, and in the means whereby the regulated closure of the door isobtained.

A represents a barrel or cylinder, within which inoves a hollow pistonor plunger, B. This piston or plunger is packed at two places within thecylinder A, as shown at c and d, and an air-passage, C, is made throughthe shell of the piston opening into the cylinder A, between the twoplaces where the piston is packed, so that the portion oi' the cylinderA between the packings and the interior of the hollow piston-rod form anair-chamber. Through this piston-rod I obtain the supply ci' airrequired to form the air-cushion by making an aperture in the rod, asshown at D, provided with a valve, which allows the inflow of air whilethe piston is moving in one direction, but which closes and prevents theoutilow of air when the piston moves in the other direction, and acts asan air-compressor.y I

alsoprovide an openin g from the piston (shown (No model.)

.at E) of suitable size, through which the conipressed air may escape asthe door closes.

E represents a coiled spring, which, for convenience, is placed withinthe same cylinder or barrel A; This spring operates vto close the doorbypressure against the piston B, which is connected with the door by thebracket G, to which it is attached. The tension of this spring E, andconsequently the force with which it acts to close the door, isregulated by means of a suitable adjusting device--preferably consistingof an abutment or bearing, H, acting against the base ofthe spring Randprovided with adjustingscrews h, whereby the pressure upon the spring,and consequently its amount ot resistance, may be regulated at pleasure.By this means I am enabled to adjust the door-check to any weight ot"door, and also to vary its power from time to time, if this, for anyreason, should become necessary, and I am also enabled to dothis whilethe door-check is in place. These adjusting-screws may conveniently bearin the cap I, which connects the cylinder A and its incloscd mechanismwith a second bracket or hinge, K, attached to the jamb of the door atthe proper location relatively to the line of the hinges, as shown inFig. l. The other end of the cylinder A is closed by a sleeve, L, whichis extended to form a bearing for the. piston-rod B.

The device operates as follows: As the door is opened the difference ofthe length of the radii on which the cylinder A and the piston B swingcauses the latter to travel through the cylinder and compress the springF, the space in the cylinder between the packings o and d and theinterior ofthe piston B being at the same time iilled with air,whicl1enters through the valve D. The compressed spring F will now force thedoor to with atension regulated as described, and this will cause thepackings d and o to approach, so that the air between them and also thatwithin the hollow piston is compressed, and thel closing of the doorretarded until the slow escape of air through the aperture E allows thedoor to gradually and noiselessly close under the spring-pressure.

I am aware that door-checks have been previously constructed ordescribed which contain the features, broadly, or" anair-compressgradually IOC ing piston connected with a spring, andattached to a door and acting within a cylinder connected with a partadjacent to such door at such a point relative to the hinges that thecylinder shall swing on a relatively shorter ra- 5 dius than the doorand piston when the door is opened and closed.

I make no claim to any of these features, broadly.

I claim- 1o 1. In a door-check, the combination, with theair-compression chamber, formed by the cylinder and the packed hollowpiston, said piston working within said cylinder and being provided withan air-vent of iixed size, of the 15 door-closing and air-compressing,`spring, and

means for regulating its tension or force, all

substantially as and for the purposes set forth. 2'. In a door-check,the combination of the following elements, to wit: an air-inclosingcylinder, a hollow perforated piston working 2o therein, a valvcdair-inlet, and an air-outlet, the said piston being packed at two placeswithin the said cylinder on either side of the perforation.

3. Inadoor-check, the hollow piston B, pro- 2 5 vided with a valvedair-inlet, an air-outlet, and an aperture, C, connecting,` the interiorof the piston with that portion of the cylinder A within which and thehollow piston the air is compressed.

In testimony whereof I have hereunto subscribed my name this 10th day ofDecember7 A. D. 1883.

STEPHEN PORTER.

Vitnesses:

OHAs. W. KNAPP, J. HENRY TAYLOR.

